Door opening apparatus

ABSTRACT

A DEVICE FOR OPENING A HATCH DOOR OR OTHER CLOSURE IN A SAFE AND POSITIVE MANNER. A PAIR OF SPRING ASSEMBLIES ARE COUPLED BETWEEN A HATCH AND ITS FRAME, ONE SPRING ASSEMBLY BEING COOPERATIVE WITH A VISCOUS DAMPING DEVICE. UPON RELEASE OF THE HATCH, THE FIRST SPRING ASSEMBLY CAUSES THE HATCH TO RAPIDLY OPEN BY A PREDE-   TERMINED AMOUNT, WHILE THE DAMPED ACTION OF THE SECOND SPRING ASSEMBLY CAUSES THE HATCH TO SLOWLY AND POSITIVELY CONTINUE TO A FULL OPEN POSITION.

Feb. 9, 1971 M. J. GOLDMAN 3,561,162

DOOR OPENING APPARATUS Filed June 16, 1969 2 Sheets-Sheet 1 Il\\'/ {NI 1 m MAURICE J GOLDMAN in w. 4447 Feb. 9, 1971 Filed June 16, 1969 M. J. GOLDMAN DOQR OPENING APPARATUS 2 Sheets-Sheet 2 "Ill 62 Fig. 4.

United States Patent O 3,561,162 DOOR OPENING APPARATUS Maurice J. Goldman, 382 Massapoag Ave., Sharon, Mass. 02067 Filed June 16, 1969, Ser. No. 833,641 Int. Cl. Ef 1/14, 5/02 US. Cl. 49386 5 Claims ABSTRACT OF THE DISCLOSURE FIELD OF THE INVENTION This invention relates to door opening apparatus and more particularly to apparatus for automatically and safely opening a hatch door or other closure member upon release of a latch maintaining the door in a closed position.

BACKGROUND OF THE INVENTION In many instances it is desirable to provide means for automatically opening a door or other closure member upon the release of a latch. For example, hatch doors are often provided on the roof of a building, these doors being automatically openable in the event of fire so that firemen can gain access to the building through the roof and, in addition, to provide an opening for release of smoke and fumes during a fire. Generally, these hatch doors are maintained in a closed position by a latching mechanism containing a fusable element which melts at a predetermined elevated temperature to permit actuation of the latching mechanism and corresponding release of the door. Automatic opening of the released door is provided by a relatively complicated arrangement of springs and/or pulleys and weights which urge the door to an open position upon release of the latching mechanism. By reason of the relative complexity of such conventional opening mechanisms, considerable expenditure of time is required for installation on a door. Such mechanisms are also relatively expensive due to their complexity and due to the cost of installation. Moreover, a conventional opening mechanism generally acts with such violent force that the rapid opening of a door can be injurious to any person who might be in the path of the door as it opens. In addition, the violent opening force of such opening mechanisms can sometimes damage the door mounting and prevent its reuse without realignment of the door and its associated frame.

SUMMARY OF THE INVENTION In accordance with the present invention, a door opening mechanism is provided which causes positive and safe opening of a hatch door or other closure member. Briefly, the invention comprises first and second spring assemblies, one assembly being cooperative with a viscous damping device to provide controlled spring expansion.

Typically, the opening mechanism is mounted between a hatch door and its associated frame. Upon release of a latching mechanism maintaining the door in its closed position, the unrestrained spring assembly is operative to cause the door to quickly pivot off its frame by a few degrees and to continue at a controlled rate in response to the viscously restrained expansion of the second spring assembly to a full open position. By the unique double action provided by the invention, the door is quickly pivoted off its mounting frame and is then caused to fully open by a controlled and positive force. The unrestrained and often violent force with which conventional automatic door openers operate is, therefore, avoided. Danger to individuals who may be in the path of an opening door is considerably reduced since, according to the invention, the door opens at a controlled rate and with controlled force which is suflicient to assure positive opening while not being injurious to persons in its path. The opening mechanism is extremely compact and occupies only a small volume within the door mounting space, and, in addition, can be installed with a minimum of time and effort.

DESCRIPTION OF THE DRAWINGS The invention will be more fully understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a pictorial view of the invention installed in a vertically openable door assembly;

FIG. 2 is an elevation view partly in section of a first spring assembly embodied in the invention;

FIG. 3 is an elevation view partly in section of a second spring assembly embodied in the invention;

FIGS. 4 and 5 are plan views of a washer and piston, respectively, employed in the assembly of FIG. 3; and

FIGS. 6A through 6B are cutaway elevation views partly in section illustrating the operating sequence of the invention.

DETAILED DESCRIPTION OF THE INVENION The invention as embodied in a vertically pivotable hatch door is illustrated in FIG. 1. A hatch door is mounted on a rectangular frame 12 and is pivotally movable with respect to the frame by hinges 14. The door is maintained in a closed position by a latching mechanism composed of a member 16 secured to the underside of door 10 and member 18 secured to the inside surface of frame 12. The door opening assembly 20 embodying the invention is mounted between the door frame and door and is illustrated in FIG. 1 in its fully opened position. The door opening assembly 20 includes an elongated coil spring 22 pivotally mounted at its lower end to a bracket 24 which is secured to an inner surface of frame 12 on the same side of the frame containing hinges 14. Spring 22 is pivotally connected at its upper end to a bracket 26 secured to a surface of door 10. Bracket 26 defines a channel containing a second elongated spring member 28 which is pivotally connected at one end to bracket 26 and to the uppermost end of spring member 22. An axle 30 pivotally connecting spring members 22 and 28 is slidably disposed within elongated slots 32 formed in respective sides of bracket 26.

The spring assembly including spring member 28 and associated mounting elements is illustrated more clearly in FIG. 2. The base of bracket 26 has secured thereto, within the channel defined by the sides of bracket 26, a cylinder 34 dimensioned to accommodate a portion of spring 28 coiled therein. A cylindrical member 36 is disposed within the turns of spring 28 and is connected at the outermost end to a rod 38 coaxial with spring 28 and secured thereto by a retaining element 40. Spring 28 is illustrated in FIG. 2 in its expanded position and it will be appreciated that upon compression of the spring, cylindrical member 36 will move inwardly of cylinder 34 and thereby act as a guide during compression of the turns of spring 28.

The second spring assembly including spring member 22 and its associated elements is illustrated more particularly in FIG. 3. Spring 22 has coaxially disposed therein a viscous damping device which includes a cylinder 42 adapted to contain a viscous fluid, such as oil. A piston 44 is slidably disposed within the cylinder 42, piston 44 being connected to a slidable piston rod 46. An O-ring 48 is provided around the periphery of piston 44 to provide sealing engagement with the wall of cylinder 42. Similarly O-rings 50 are provided in the upper end of cylinder 42 to provide sealing engagement with piston rod 46 slidable therein. The upper end of rod 46 is secured to mounting plate 52 such as by the threaded portion illustrated, plate 52 also serving to engage the upper end of spring 22 by means of axle 30. Spring 22 is engaged at its lower extremity by a flange 54 provided on the lower end of cylinder 42. A pivot pin 56 is provided in the lower end of cylinder 42 for mounting to bracket 24, as illustrated in FIG. 1. Piston 44 includes a plurality of holes 58 formed through the piston around the annular region thereof, the holes 58 terminating at the upper surface of piston 44 in an annular groove 60. A washer 62 is slidably disposed around piston rod 46 and contains a lesser plurality of openings 64 which are in alignment with the annular groove 60 formed in the upper surface of piston 44. A retaining pin 66 is secured through rod 46 to limit the slidable travel of washer 62. If desired, a sleeve can be employed over spring 22 to prevent dirt accumulation.

The viscous damping device 40 is operative to provide a restraining force during upward movement of piston 44 within cylinder 42 and to provide a lesser restraining force during downward movement of piston 44 within the cylinder. In FIG. 3, spring 22 is illustrated in its fully compressed position as it would be when door is closed. Expansion of spring 22 to its fully opened or extended position against the urging of the viscous restraint is provided by the unique damping mechanism. Thus, spring 22 expands at a controlled rate and with controlled force to provide a smooth and predetermined opening force to door 10. The differential viscous restraint is provided by operation of the slidable washer 62. As piston 44 moves upward within cylinder 42 the viscous fluid within the cylinder is caused to flow through openings 64 and thence through openings 58 to the opposite side of piston 44. During downward movement of piston 44, viscous fluid is caused to flow through openings 58, the force of the fluid emanating from openings 58 causing washer 62 to move away from piston 44 and into engagement with retaining pin 66. Since there is a greater plurality of openings 58 within piston 44 than the plurality of openings 64 within slidable Washer 62, a greater flow of viscous fluid is permitted during downward motion of the piston than during upward motion thereof. Openings 64 can be aligned with selected ones of the openings 58 in piston 44, for example by a key or other suitable means (not shown) for preventing rotational movement of washer 62 about rod 46. Such alignment is not essential, however, since annular groove 60 can be dimensioned to accommodate the flow of fluid from openings 64 to openings 58. Differential flow can also be provided by employing smaller sized openings 64 with respect to openings 58.

The operation of the invention in opening a door from a latched position to a fully opened position is illustrated in FIGS. 6A through 6E. One side of a frame 70 of a hatch door assembly is secured to a structural member 72 of a building or other structure with which the door is employed. The hatch door 74 is pivotally connected to frame 70 by means of one or more hinges 76. The door opening apparatus 20 embodying the invention is secured between frame 70 and door 74. In the fully closed position as illustrated in FIG. 6A, door opening apparatus 20 is disposed substantially parallel to the wall of frame 70 i on which it is mounted, and with springs 22 and 28 in their fully compressed state. Upon release of the latching mechanism, door 74 raises under the influence of the unrestrained spring assembly to an initial open position illustrated in FIG, 6B. Spring 28 expands at least partially,

causing door 74 to raise to a predetermined elevated position. Spring 24 remains substantially compressed at this point in the operating sequence. Spring 28 continues to expand to its fully extended position while spring 22 expands at a controlled rate determined by viscous damping device 40 to cause door 74 to be raised to its fully opened position. As seen in FIGS. 6C through 6E, axle 30 travels downwardly in the slots provided in bracket 26 as spring 28 expands and as door 74 pivots to its fully opened position. In the fully opened position illustrated in FIG. 6E, the bracket 26 attached to door 74 is substantially at right angles to spring 22, with axle 30 being disposed at the opposite extremity of the guide slots. The reverse sequence occurs upon closure of the door onto its mounting frame. Various modifications and alternative implementations will now occur to those versed in the art without departing from the spirit and true scope of the invention. For example, the invention can also be employed with horizontally pivotable doors.

What is claimed is: 1. Door opening apparatus comprising: a first spring assembly adapted for attachment to a pivotally openable door; a second spring assembly adapted for attachment to the frame of a pivotally openable door; and a damping device cooperative with said second spring assembly; said first and second spring assemblies :being pivotally connected together and operative sequentially to cause opening of said door to a predetermined first position at a first rate and controlled opening of said door to a predetermined second position at a second rate slower than said first rate. 2. Apparatus according to claim 1 wherein said first spring assembly includes:

a first mounting bracket adapted for attachment to a pivotally openable door; and a compressable spring mounted on said bracket; and said second spring assembly includes: a second mounting bracket adapted for attachment to the frame of said door; an elongated compressable spring disposed around said damping device; means pivotally connecting one end of said damping device to said second mounting bracket; and means including a mounting plate pivotally connecting the other end of said damping device to said first spring assembly. 3. Apparatus according to claim 2 wherein said damping device includes:

a cylinder adapted to contain a viscous fluid; a piston disposed for slidable movement within said cylinder and through said fluid; means cooperative with said piston for permitting movement of said piston through said fluid in a first direction at a first rate and movement through said fluid in an opposite direction at a second rate faster than said first rate; a piston rod attached at one end to said piston and at the other end to said mounting plate; said viscous damping device being operative to control the rate of expansion of said elongated spring. 4. Apparatus according to claim 3 wherein said piston includes a plurality of openings for-med therein and operative during movement of said piston through said fluid in a first direction to permit passage of fluid therethrough at a predetermined first rate; and said means associated with said piston includes a lesser plurality of openings formed therein and disposed in alignment with certain of said openings in said piston, and operative, during movement of said piston through said fluid in an opposite direction, to permit passage of fluid therethrough at a predetermined second rate slower than said predetermined first rate.

5. Apparatus according to claim 3 wherein said first spring assembly includes:

a first mounting bracket adapted for attachment to a pivotally operable door and having guide slots disposed therein;

a first plate having an axle disposed for slidable movement in said guide slots; and

a compressable spring mounted between said bracket and said first plate; and

said second spring assembly includes:

a second mounting bracket adapted for attachment to the frame of said door;

means pivotally connecting one end of the cylinder of said damping device to said second mounting bracket; and

a second plate attached to the distal end of the piston of said damping device and pivotally connected to said first plate; and

an elongated compressable spring disposed around said damping device and mounted between said second pivotal means and said second plate.

References Cited UNITED STATES PATENTS FOREIGN PATENTS 1,117,523 11/1961 Germany 49386 I KARL BELL, Primary Examiner US. Cl. X.R. 

